DISOXTDATION EFFECTED BY THE ALKALINE PEEOXIDES. 
851 
It is undoubtedly difficult to speak with any great probability as to the nature of the 
specific changes which take place, in regard to which many hypotheses may be formed. 
The following view, however, is in accordance with the facts. 
1 . When x=l, we have the formation and subsequent decomposition of the substance 
Cr4 O9, according to the equations 
2 Cr2 O3 + 3 H2 O2 = Cr^ O9 + 3 H2 O , 
Ciq Oy = Cr4 O3 + 3 O2. 
2 . When x= 2 , after the reaction just expressed the substance Cr4 Og is further oxi- 
dized to the oxide Cr4 Oj2, according to the equation 
Cr4 Oy-j- 3 H 2 02 =Cr 4 O42+3H2 O. 
The body Ciq Oj2 further decomposes with the excess of peroxide of hydrogen present, 
possibly with the formation of the higher oxide of hydrogen, H2 O3, and the former pro- 
duct, Cr4 Oy, 
Cr 4 O42+3H2 02=Cr4 Oy-l- 3 H 2 O3. 
That the product of the fii’st action is in a continual state of formation and decom- 
position during the change, is probable from the greater permanence of the blue com- 
pound when an excess of peroxide of hydrogen is present : the presence of this body, 
which in a small excess of peroxide of hydrogen has only a momentary existence, is 
rendered evident by the duration of the blue colour for as long as ten minutes in the 
presence of an excess of the peroxide. Lastly, the substance Cr4 Oy decomposes very 
much more rapidly than the substance H2 O3, ^. e. than the other oxidized product ; so 
that the decomposition can be broken up into its several stages in the manner described, 
the chemical changes which take place being represented by the system of equations, 
201-2 03 +3H2 02= 01-4 Oy 4-3H2 0, 
01-4 Oy + 3 H 2 02= Cr4 042 + 3 H 2 0, 
01-4 O42+ 3H2 02= 01-4 Oy + 3 H2 O3, 
Cr4 Oy = Cr4 O3 -f" 3 O2, 
3H2O3 = 3 H 2 02 + 30 ; 
and the result of these changes, by the equation which results from elimination between 
them, namely, 
2 Cr 2 03 + 6 H 2 02=01-4 O3+6H2 0 + 90 . 
Since the amount of oxygen is in all probability given olf in successive stages, we cannot 
fix with certainty upon any one degree of oxidation as the blue compound *. 
* I am unable to reconcile my own results with those of Baeeeswil, whose experiments appear to have 
been carefully conducted. The reaction according to this chemist is 
2 Crg 03+112 02= Cr4 07+1120 
Cr4 O7 = Cr4 O3 + 2 O2, 
the analogue of permanganic acid being formed. I have not, however, repeated the experiment precisely in 
the form in which it was made by him, and it is possible that under certain circumstances the oxidation 
may be arrested at this point. See Annales de Chimie, vol, xx. p. 364 . 
